Question

Given the vectors b = Dr and
c = xr, where r is the position vector and D is a constant, calculate (Curl) :∇ × b and ∇ × c

Answer 1

∇ × b = D∇×r + ∇DXr
can you do it now ?

Answer 2

i have to go so ill give the answer
∇ × b = ∇ × Dr = D∇×r + ∇DXr ->

if you check ∇×r = 0 so D∇×r = 0
and ∇D = 0 since its constant so
∇ × b = 0

∇ × c = ∇ × xr = x∇×r + ∇x X r = 0 + ∇x X r = (0,-z,y)

Answer 3

you can as well put the constant on the x right into the r vector and calculate the curl directly .. (instead of using my method)

Answer 4

was helpful, thank you